1. Field of the Invention
The present invention relates to forming devices for bevelling, and particularly to forming devices which can readily form bevels at small angles.
2. Prior Art
Products having gentle slopes are now universally used in modern industries. Such slopes are often formed by a grinding wheel of a grinder. The grinding wheel has a circumferential working surface, and the working surface is frequently beveled at an edge thereof. The bevel is generally formed by cutting the working surface with a forming device.
FIG. 4 show a conventional forming device 10 for bevelling. The forming device 10 comprises a base 12, a rail 14, a horizontal bar 16, and a workbench 18. A pair of support arms 22 extends upwardly from one side of the base 12. A pair of coaxial pivot holes 24 is respectively defined in the support arms 22. An axle 25 is pivotably received in the pivot holes 24. One end of the rail 14 is fixedly connected to the axle 25. The rail 14 is thus pivotable relative to the base 12. The bar 16 is fixed to an underside of an opposite end of the rail 14. A support plate 26 with a machined top surface is integrally formed on a top face of the base 12. The bar 16 abuts against the machined surface of the support plate 26. A beveller 32 is installed in a top surface of the workbench 18. In an initial position, the rail 14 is horizontal.
In operation, the forming device 10 is placed on a grinder (not shown). A gauge (not shown) is placed between the bar 16 and the support plate 26. The rail 14 thereby rests above the gauge at an angle, and the workbench 18 rests on the rail 14 at a corresponding angle. A grinding wheel (not shown) fixed on the grinder is located above the workbench 18, with the axis of the grinding wheel perpendicular to the axle 25. The grinding wheel is rotated at high speed. The workbench 18 is slidably moved along the rail 14 to contact and cut an edge of the grinding wheel. A circumferential surface with a bevel is thus formed on the grinding wheel.
Gauges having discrete thicknesses according to industry standards are widely used in this process. When a grinding wheel with a bevel of greater than one degree is needed, a single standard gauge or combination of different standard gauges can be used with the forming device 10. However, when a grinding wheel with a bevel of less than one degree is needed, there is no standard gauge available. A special thin gauge must be manufactured for use with the forming device 10. It is difficult and time-consuming to manufacture such thin gauge.
Accordingly, an object of the present invention is to provide a forming device which can form a bevel of less than one degree using standard gauges.
Another object of the present invention is to provide a forming device which can form two different bevels using a single standard gauge.
To achieve the above-mentioned objects, a forming device for bevelling in accordance with the present invention comprises a base, a rail, a workbench and a bar. The base has a support plate integrally formed on a top surface thereof. The support plate has a precision-machined surface. A pair of support arms extends upwardly from the base. A pair of coaxial pivot holes is respectively defined in the support arms, and an axle is received in the pivot holes. One end of the rail is fixedly connected with the axle. The rail is thereby pivotable relative to the base. The workbench rests on the rail, and is slidably moveable along the rail. A beveller is fixedly installed in a top surface of the workbench. The bar is fixedly connected to an underside of an end of the rail that is opposite to the end where the axle is connected. The bar comprises a large bar abutting the precision-machined surface, and a coaxial small bar. The rail can be adjusted to allow the forming device to bevel at an angle of less than one degree, by placing one or a combination of standard gauges between the small bar and the support plate.